diff --git a/src/test/java/de/neemann/digital/hdl/TestHDLExportFlag.java b/src/test/java/de/neemann/digital/hdl/TestHDLExportFlag.java
index 6d1f4cec0..96f18f7b2 100644
--- a/src/test/java/de/neemann/digital/hdl/TestHDLExportFlag.java
+++ b/src/test/java/de/neemann/digital/hdl/TestHDLExportFlag.java
@@ -5,20 +5,59 @@
  */
 package de.neemann.digital.hdl;
 
+import de.neemann.digital.core.basic.*;
 import de.neemann.digital.core.element.ElementTypeDescription;
+import de.neemann.digital.core.io.*;
+import de.neemann.digital.core.wiring.Clock;
+import de.neemann.digital.core.wiring.Splitter;
+import de.neemann.digital.draw.elements.Tunnel;
 import de.neemann.digital.draw.library.ElementLibrary;
 import de.neemann.digital.hdl.vhdl2.entities.VHDLTemplate;
+import de.neemann.digital.testing.TestCaseElement;
 import junit.framework.TestCase;
 
+import java.util.HashSet;
+
 public class TestHDLExportFlag extends TestCase {
 
+    private static final HashSet<ElementTypeDescription> implicitSupported = new HashSet<>();
+
+    static {
+        implicitSupported.add(And.DESCRIPTION);
+        implicitSupported.add(NAnd.DESCRIPTION);
+        implicitSupported.add(Or.DESCRIPTION);
+        implicitSupported.add(NOr.DESCRIPTION);
+        implicitSupported.add(XOr.DESCRIPTION);
+        implicitSupported.add(XNOr.DESCRIPTION);
+        implicitSupported.add(Not.DESCRIPTION);
+
+        implicitSupported.add(Out.DESCRIPTION);
+        implicitSupported.add(In.DESCRIPTION);
+        implicitSupported.add(Clock.DESCRIPTION);
+
+        implicitSupported.add(Ground.DESCRIPTION);
+        implicitSupported.add(VDD.DESCRIPTION);
+        implicitSupported.add(Const.DESCRIPTION);
+
+        implicitSupported.add(Tunnel.DESCRIPTION);
+        implicitSupported.add(Splitter.DESCRIPTION);
+
+        implicitSupported.add(TestCaseElement.TESTCASEDESCRIPTION);
+    }
+
     public void testHDLExportFlag() {
         ElementLibrary lib = new ElementLibrary();
         for (ElementLibrary.ElementContainer ec : lib) {
             ElementTypeDescription etd = ec.getDescription();
             boolean hdlExportFlag = etd.isSupportsHDL();
-            if (VHDLTemplate.isTemplate(etd))
+            boolean isTemplate = VHDLTemplate.isTemplate(etd);
+            if (isTemplate)
                 assertTrue("HDL template available for " + etd.getName(), hdlExportFlag);
+            else {
+                if (hdlExportFlag && !implicitSupported.contains(etd))
+                    fail(etd.getName() + " is flagged as supporting HDL");
+            }
         }
     }
+
 }